Contact breaker wire.

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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Contact breaker wire.

Postby Pharisee » Fri Jan 12, 2018 10:49 pm

On the later models with coil ignition the wire from the contact breaker exits through the rear of the outer timing cover. The coil is mounted on the frame, under the tank. Which way is the cable routed between the coil and the contact breaker?

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Re: Contact breaker wire.

Postby Mick D » Sat Jan 13, 2018 9:23 am

Hi

From the CB cover across to a convenient hole in the RH engine plate, back under the cover to the frame down tube, up the down tube and forward along the top tube to the coil. This is as per the original loom.

CB Wire Route.png


Regards Mick
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Re: Contact breaker wire.

Postby Pharisee » Sat Jan 13, 2018 10:30 am

Thanks, Mick. That helps but that wire does look vulnerable. I'll look at putting it in some sort of sleeving. According to the 1960 parts list, the rubber grommet is #024159. That's not listed on the AMOC Spares website. Any idea where I might obtain one?
Thanks, John.

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Re: Contact breaker wire.

Postby Mick D » Sat Jan 13, 2018 10:50 am

Hi John

Steve at AMC Classic supplied mine under that part number.

Agree it does look a little exposed but I try to keep things looking original where I can - unseen in the photo are about three layers of heat shrink tubing which make up the difference in diameter between the wire and orifice in the grommet and provide a water seal. Still looking for a suitable split rubber tube to stop the wire potentially chaffing as it goes through the engine plate.

Regards Mick

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Re: Contact breaker wire.

Postby Pharisee » Mon Feb 26, 2018 5:31 pm

I bought a short length of silicone tubing, sold for turbocharger valves apparently. It's 3mm bore x 7mm O/D. The wire is a nice fit in the bore and the tube is a good push fit into the grommet hole in the timing cover. Not original perhaps but it will protect the vulnerable wire and be as good a seal as the grommet was.

IMG_0515-small.jpg


IMG_0513-small.jpg
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Re: Contact breaker wire.

Postby Mick D » Mon Feb 26, 2018 5:52 pm

Hi

That eye end crimp looks a bit on the large size, (I opened out a smaller one to exactly fit the CB post) - are you using a larger washer?

Regards Mick

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Re: Contact breaker wire.

Postby Pharisee » Mon Feb 26, 2018 6:36 pm

Mick D wrote:Hi

That eye end crimp looks a bit on the large size, (I opened out a smaller one to exactly fit the CB post) - are you using a larger washer?

Regards Mick


I had to drill that one out a little. It's a perfect fit for the plastic bush on the contact set. The washer supplied with the new contacts is approximately the same diameter as the brass eye.

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Re: Contact breaker wire.

Postby bodgert » Tue Feb 27, 2018 3:22 pm

Does it not make more sense to put the grommet hole in the crankcase so that the cover is not restricted

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Re: Contact breaker wire.

Postby Pharisee » Tue Feb 27, 2018 4:43 pm

bodgert wrote:Does it not make more sense to put the grommet hole in the crankcase so that the cover is not restricted


I would have thought so too (well, the inner timing cover anyway) but hey... I didn't design it!

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